Boiler



E. P. EDGAR.

BOILER. N 555 23 Patented Feb. 25, 1896.

Z4 ATTORNEY UNITED STATES.

PATENT OFFICE.

ELLIS F. EDGAR, OF \VOODBR-IDGE, NEIV JERSEY.

BOILER.

SPECIFICATION forming part of Letters Patent No. 555,236, dated February25, 1896.

Application filed September 17,1895. Serial No. 562,757. (No model.)

To all whom it may concern:

Be it known that I, ELLIS F. EDGAR, a citizen of the United States ofAmerica, and a resident of Woodbridge, in the county of Middlesex andState of New Jersey, have invented certain new and useful Improvementsin Boilers, of which the following is a specification, reference beinghad to the accompanying drawing, forming part of the same, in which thefigure represents a central vertical section of a boiler embodying myinvention, the smoke-box and draft-pipe being omitted.

My invention relates to boilers for generating steam; and it consistsessentially in contracting the fire-tubes at or about the waterline ofthe boiler.

I have discovered that for very many reasons it is advantageous to uselarge fire-tubes, as they are more durable, requiring less repairs, andthey do not choke the fires and impair combustion to the degree thatsmaller tubes do; but I have also found that to employ large tubes asordinarily constructed entails a great waste of fuel, and accordinglylarge expense in running, which I am enabled to avoid by means of theinvention about to be described, which, as stated, consists essentiallyin contracting said tubes at or about the water-line of the boiler. I amthereby enabled to cause a large body of flame, highlyheated air andgases to enter the tubes and thereby greatly heat them and thesurroundin g water; but as this heat is rapidly absorbed by the watersurrounding the tubes, and the absorption of such heat reduces thevolume of the air and gas that has entered the tube, I do not need solarge an exit or so large a draft-space from the point where there is nowater to absorb the heat. Consequently I may at that point reduce saidspace by contracting the tube, and thus prevent the drivin g throughinto the smoke-box and the draftexit of large quantities of heat andunconsumed heat-producing material before it has had an opportunity todo the work desired, which would occur were the tubes left of one sizeand uninterrupted throughout, and yet, because of the reduction ofvolume noted, such contraction will not choke or sweat the fires, sothat I utilize the advantages of large tubes without being damaged bythe ordinary disadvantages.

In the drawing I have shown a vertical shell boiler with a brickworkfurnace F, having ash-pit A, ash-door opening cl, grate-bars G, fire-door opening D, outer shell S, tu be-sheets T and T, tubes 25 and t,water-leg L, and separator or spray plate .9.

The novelty is in the fire-tubes, which, it will be noticed, arecontracted at or about the water-line, most of them by merely drawing inthe tubes themselves near that point, as at 0; but I may vary thisarrangement and provide for the contraction by using a small section ofsmaller tubing at that point and joining two sections of larger tubingto it, as seen at the second tube from the right-hand side of thedrawing. So too, after drawing in the tube, I may maintain the smallerdiameter from about the water-line to the succeeding tube-sheet, asshown in the extreme righthand tube.

To avoid priming, which is likely to take place in boilers that are soarranged as to heat the fire-tubes very rapidly, I surround them by whatI term circulator-tubes 2f, reaching from near the lower ends of thefire-tubes to about the water-line ora trifle above it, as shown, and toinsure these tubes shall hold their places, and to provide anentrance-way for the water at the bottom, I usually support them alittle above the level of the lower tube sheet by legs Z.

The parts of the tubes 75 above the waterline would naturally be veryhighly heated, and though the contraction mentioned does insure that thegreater part of the heat shall be absorbed and utilized below thewater-line, and thereby decrease the danger of burning the tubes outabove that line, I still prefer to.

line them from the contraction upward with fire-clay f or somesubstantially equivalent substance, thereby practically insuring thelife of that end of the tube shall equal that of the other end.

Steam arising from the heated water will move laterally to and aroundthe edge of spray-plate .9 into the steam-space above it, and any partof the water thrown up by ebul; lition will be stopped by the plate andfall back into the main body, leaving the steam in the steam-space dry.

What I claim as my invention, and desire to secure by Letters Patent,is-- The combination in a vertical tubular boiler of fire-tubes Whosewalls are contracted substantially at the water-line andcirculatortubes, open at the bottom, surrounding said 5 fire-tubes andextending to about the level of said Water-line all substantially as setforth. In testimony that I claim the foregoing as my invention I havesigned my name, in pres ence of two witnesses, this 13th day ofSeptember, 1895.

E. F. EDGAR. Witnesses:

M. SLoUGH, A. G. N. VERMILYA.

